Headlines: Ozone Layer Under Threat Yet Again

March 11, 2014 – University of East Anglia researchers have discovered four new man-made gases, three chlorofluorocarbons (CFCs) and one hydrochlorofluorocarbon (HCFCs), that are impacting the ozone layer. The research indicates that an estimated 74,000 tons of these gases were emitted into the atmosphere prior to 2012. When compared to the more than one million tons emitted each year in the 1980s that doesn’t seem a lot. But the researchers expressed concern in their report because the human source for these new ozone-depleting gases is not known. Will the volume increase or is the presence of the gases in current quantity all that we will see?

New CFCs and HCFCs were detected in samplings from Greenland snow and from relatively unpolluted air in Tasmania. Samplings date from 1978 and 2012. All indicate that the four new gases are of recent release and have been accumulating.

Why is it of concern? After all it is only 74,000 tons when compared to the more than one million tons per year humans used to produce back in the latter part of the 20th century. The gases which were invented in the 1920s are composed of carbon, chlorine and fluorine. In combination these slowly degrade. As a result they have the time to rise into the stratosphere where the chlorine component contributes to ozone destruction. When compared to natural occurring chlorine the CFCs and HCFCs are far more destructive. That’s because chlorine on its own degrades much faster and because of its high specific gravity never reaches into the stratosphere.

CFCs and HCFCs were banned completely as of 2010 based on an international signed agreements dating back to 1989. But the gases have a nasty habit of hanging around from between 20 and 120 years before the ultraviolet rays emitted by the Sun deplete them. That’s the problem because the gases have plenty of time to mix in the lower atmosphere and rise into the stratosphere where they do their damage. Without the protective ozone layer those ultraviolet rays get through and contribute to rates of occurrence of cancer and cataracts.

Currently ozone has been disappearing from the upper atmosphere at the rate of 4% per decade for the last 30 years. That is happening despite the ban on CFCs and HCFCs. That’s because of the longevity of the gases already released. These new human created suspects may turn out to be producers of insecticides and solvents. The search is on to find out who are the culprits. We may never know.

lenrosen4
Len Rosen lives in Toronto, Ontario, Canada. He is a researcher and writer who has a fascination with science and technology. He is married with a daughter who works in radio, and a miniature red poodle who is his daily companion on walks of discovery.
More...